Essentially all types of rubber, both natural and synthetic, and particularly rubbers formed from dienes are known to be susceptible to deterioration resulting from prolonged exposure to oxygen, ozone, light and heat. A great deal of effort has been expended by those engaged in the field of polymer technology to develop various antidegradants that will effectively inhibit the adverse effects of aging of polymeric compositions. In addition, much work has been done to discover new ways to prevent antidegradants from leaving polymer compositions by extraction, migration or volatilization. One particular area of concern deals with the antidegradants used in the tire industry where improvements in the polymers or polymer blends have increased the serviceable life of the tires thus prolonging the exposure to the degradative effects mentioned above.
One approach taken to overcome the problems of extraction and volatilization has been to use compounds of higher molecular weight such as has been disclosed in U.S. Pat. Nos. 3,975,414 and 4,152,319. Another approach has been to use an antidegradative monomer which polymerizes to become part of the polymer as has been disclosed in U.S. Pat. Nos. 3,658,769 and 3,817,916. Still another approach has been to graft a reactive antidegradant onto an existing polymer chain as disclosed in U.S. Pat. No. 4,155,955.